The graphic, being so simplistic and not carrying any trademark or other registrable intellectual property, is not covered by most countries' copyright laws.
The graphic is used so widely and freely and for long enough without any recorded incidence of anyone following up a copyright issue that even were it once considered copyright, a court is likely to consider it passed into public domain..
From ''http://en.wikipedia.org/wiki/Image:Rssicon_3614.gif'': RSS (file format) Icon ''Copyright'' is believed to be free on this: # The [http://blogs.law.harvard.edu/tech/rss#licenseAndAuthorship RSS Specification] itself is under copyleft according